In recent years, individual recognition technology has received a lot of attention. For example, there is a technology to be used for production and management, in which information such as a history of an individual object is clarified by giving an ID (an individual recognition number) to the object. Above all, the development of semiconductor devices that can transmit and receive data without contact has been advanced. As such semiconductor devices, an RFID (Radio Frequency Identification) tag (also referred to as an ID tag, an IC tag, an IC chip, an RF (Radio Frequency) tag, a wireless tag, an electronic tag, or a wireless chip) and the like are beginning to be introduced into companies, markets, and the like.
Further, embedding an IC chip in paper has been suggested, and since incorporating an IC is easy, there is demand for embedding an IC chip in paper in a papermaking process. For example, in Patent Document 1: Japanese Published Patent Application No. 2002-298118, embedding an IC chip between paper layers using a cylinder paper machine is mentioned. Also, in Patent Document 2: Japanese Published Patent Application No. 2001-230269, paper embedded with an IC chip is manufactured by letting the IC chip sink in a raw material of paper that is dissolved in water, and then drying the raw material of paper while applying pressure with a roller.
In Patent Document 1, the IC chip is simply embedded in multilayered paper, and there is no consideration for flatness or flexibility of the portion in which the IC chip is embedded. In Patent Document 2, since an IC chip that is cut out of a silicon wafer is used, flexibility of a portion in which the IC chip is embedded is reduced.